Apparatus for dividing flow



Sept 13 1965 R. D. LIVINGSTON APPARATUS FOR DIVIDING FLOW 2 sheets-sheet2 l Filed March 5, 1964 www Wmv

, INVENTOR United States Patent O ice 3,272,231 Patented Sept. 13, 19663,272,231 APPARATUS FOR DIVIDING FLOW Richard Donnan Livingston,Seaford, Del., assignor to E. I. du Pont de Nemours and Company,Wilmington, Del., a corporation of Delaware Filed Mar. 5, 1964, Ser. No.349,635 8 Claims. (Cl. 137-561) This invention relates to thedistribution of a viscous uid under laminar ow conditions from a singlesource to a plurality of delivery ports and more particularly to animproved apparatus for insuring proper splitting of the viscous fluid.

Systems for distributing liquids from a .single source to a plurality ofdischarge points are common and various systems have been employed in anattempt to provide even distribution of the liquid. A tree-like cascademanifold is one known convenient way of d-ividing a main stream ofliquid into several streams. Y

Generally, no diiiiculty is encountered in the use of the known systemsfor distribution where the liquid is of low viscosity and relativelystable. However, with -highly viscous, relatively unstable systems suchas encountered in the handling of molten streams. of high polymers suchas nylon and polyethylene terephthala-te, the problem of maintainingequal residence times in a distribution system for the various streamsbecomes severe. This is particularly true in the distribution of aymolten polymer, such as nylon, to a plurality of devices havingextrusion oriiices, since the physical properties of the polymer changewith time at high temperature. The differences in residence time to thevarious streams lead to non-uniformities in the final products of theextrusion orifices.

It is also essential in such a distribution system that there be no deadspots where polymer can hold up, stagnate and then Slough-off and owinto the main stream and cause degradation of the final product. Theelimination of dead spots in round piping is quite simple. However, atthe distribution points, that is, the Ts or flowsplitting junctions,there is a considerable number of dead spots at the junction of roundconnections. This invention seeks to eliminate these dead spots in theflow splitters.

It is the object of this invention to provide an improved apparatus for-the proper distribution or splitting of viscous liquids from a singlesource to a plurality of delivery ports, without any dead spots forstagnation of time-dependent materials. Another object is to provide asimple economical apparatus for accomplishing this. Other objects willbecome apparent from the description and discussion to follow.

The improved flow splitter apparatus of this invention comprises a bodymember having a circular inlet port therein, a plurality `ofequi-spaced, coplanar discharge ports substantially perpendicular to theaxis of the inlet port and each having an identical circular exitportion and tapering to an identical rectangular cross-section at theintersections with the inlet por-t. In the preferred embodiment, thedimensions of the rectangular cross-section are such that the longerside, parallel to the plane of the discharge por-ts, is equal to orgreater than the diameter of the circular exit portion, and t-he shorterside is less than one-half the diameter of the circular cross-sections.

Reference is made to the 'accompanying drawings in which:

FIGURE 1 is a cross-sectional view of a ow splitter for splitting aninlet stream into live branch streams;

FIGURE 2 is a section view taken along lines 2 2 of FIGURE 1;

FIGURE 3 is a section view taken along lines 3-3 of FIGURE 2;

FIGURE 4 is a cross-sectional 'view of another embodiment of a splitter;

FIGURE 5 is a section view taken along lines 5-5 of FIGURE 4; and

FIGURE 6 is a section view taken along lines 6 6 of FIGURE 5.

Illustrated in FIGURES 1, 2 and 3 is a live-point splitter 10 whichcomprises body member 12 having therein inlet port 14 leading to thelive exit ports 16. The inlet port 14 is circular through its entirelength while exit ports 16 are circular at the exit ends but taper to arectangular opening 18 at the intersection with the inlet port 14. Inthis embodiment, the width yof the rectangular opening is the same asthe diameter of the exit port 16. The exit ports 16 and the rectangularopenings 18 are coplanar; the plane being perpendicular to the axis ofthe inlet port 14. The height of the rectangular opening 18 is less thanthe diameter of the circular exit port 16. It is, of course, -to berecognized that when this flow splitter is used for the distribution ofmolten polymers, the flow splitter 10 is suitably encased in a heatedjacket.

In use, the molten polymer is brought to the inlet port 14, ows to thecenter of body member 12 where it is split into five separate streams.The polymer leaves the inlet por-t area through the rectangular openings18. These rectangular openings 18 intersect one another in such a mannerthat there are no dead spots at the distribution point. Equal portionsof the fast-moving innercore material and slower-moving outer-materialcoming -in inlet port 14 are distributed to each exit port 16. With theat bottom of the inlet port 14 and the rectangular openings 18, themolten polymer sweeps clean as it moves to the exit port 16. There areno recesses, crevices or dead zones rwhere molten polymer can be held-upand either degrade or change characteristics due to a longer time at theelevated temperature.

In FIGURES 4, 5 and 6 another embodiment is illustrated. Similar to thetive-point splitter 10, the fourpoint splitter 20 consists of bodymember 22 with a circular inlet port 24 and four circular exit ports 26.The exit ports 26 taper to rectangular openings 28. In this embodiment,the height of the rectangular opening 28 is less than the diameter ofthe exit port 26 and the width of the rectangular openings 28 is largerthan the diameter of the exit port 26. While t-he taper of the fivepointsplitter 10 between the exit port 16 and the rectangular port 18 has asi-mple angle, the ltaper on the four-point splitter 20 has a compoundangle. Either can be used with either embodiment, depending upon thedesign that is desired. The essential point is that there are no deadspots between the inlet port 24 and the openings 28, and betweenadjacent openings.

Also shown in FIGURE 4, in dashed-outline form, is opening 30 into whichcan be 4placed a temperature or pressure probe. The only limitation onthis probe is that it ts into opening 30 in such a manner that no deadspot-s develop.

These flow splitters can be used in any distribution system. Forexample, they could be advantageously utilized with a screw meltersupplying molten polymer which would first go to a five-point splitterand then to tive four-point splitters, thus distributing to 20 extrusionheads from a single source of supply. Another variation that Imight beused is to have a threeor four-point splitter after the source ofpolymer melt, each exit from the splitter leading to a plurality of`distribution systems such as that shown by U.S. Patent 3,103,942,issued to Sharp, dated September 17, 1963.

While any known machining technique can be used, the preferred -methodof -making these splitters is by the investment casting process.

Specilic examples of the ldimensions of the flow splitters of thisinvention can be given. These examples are intended to be merelyillustrative of the invention but not in limitation thereof. The widthof the rectangular opening represents the longer side and is parallelwith the plane of the discharge ports. The rst example is a tivepointsplitter with the inlet port having a diameter of .891 inch, the exitports having diameters of .577 inch, the width of the rectangularopening being .577 inch, and the height of the rectangular opening being.180 inch. The total included angle of the taper -from the exit port tothe rectangular opening is 20.

A second example is a four-point splitter with the diameter of the inletport being .577 inch, the diameter of the exit port being .286 inch, thewidth of the rectangular opening being .500 inch and the height of therectangular opening 18 being .080 inch.

A third example is a three-point splitter with the diameter of the inletport being 2.24 inches, the diameter of the exit port being 1.94 inches,the width of the rectangu, lar opening being 1.94 inches and the height-of the rectangular opening being .84 inch.

Referring to the terminal portions of inlet ports 14 and 24 in FIGURES 1and 4 respectively, it should be recognized that the configuration doesnot have to be flat. For example, the terminal portion could be in theshape of a pyramid or be conical or be some rosette-type of shape whichwould Iproject above or below the plane of the flat bottom. The onlyrequirement is that the terminal portion should be radially symmetricalwith respect to the exit ports.

It i-s to be understood that the foregoing description is by way ofexample only and that various modifications and changes in the detailsmay be made without departing from the spirit of the invention and thescope of the following claims.

What is claimed is:

1. An improved ilow splitter apparatus for the distribution of a viscousliquid from a single inlet to a plurality of -outlets which comprises abody member having a single inlet port therein, a plurality ofequi-spaced, coplanar discharge ports substantially perpendicular to theaxis 0f said single port and each having a circular exit portion andtapering to a rectangular cross-section in contact with said sin-gleinlet port.

2. An improved flow splitter apparatus for the distribution of a viscousliquid from a single inlet to a plurality of outlets which comprises abody member having a single inlet port therein, a plurality ofequi-spaced, co

planar discharge -ports substantially perpendicular to the axis of saidsingle port and each having a circular exit portion and tapering to arectangular cross-section in contact with said single inlet port, andthe dimensions of said rectangular cross-section bein-gl such that thelonger side,

parallel with the plane of said discharge ports, is equal to' or greaterthan the diameter of said circular exit portion; and the Ishorter sideis less than one-half the diameter ofl said circular exit portion.

3. The improved flow splitter apparatus of claim 2 wherein there are veequi-spaced, coplanar discharge ports. l

4. The improved flow splitter apparatus of claim 3 wherein the longerside of said rectangular cross-section is equal to the diameter of `saidcircular exit portion.

5. The improved ilow splitter apparatus of claim 2v wherein there are`four equi-spaced, coplanar discharge ports.

6. The improved flow splitter apparatus of claim 5y No references cited.

M. CARY NELSON, Primary Examiner.

W. CLINE, Assistant Examiner.

1. AN IMPROVED FLOW SPLITTER APPARATUS FOR THE DISTRIBUTION OF A VISCOUSLIQUID FROM A SIGNAL INLET TO A PLURALITY OF OUTLETS WHICH COMPRISES ABODY MEMBER HAVING A SINGLE INLET PORT THEREIN, A PLURALITY OFEQUI-SPACED, COPLANAR DISCHARGE PORTS SUBSTANTIALLY PERPENDICULAR TO THEAXIS OF SAID SINGLE PORT AND EACH HAVING A CIRCULAR EXIT PORTION ANDTAPERING TO A RECTANGULAR CROSS-SECTION IN CONTACT WITH SAID SINGLEINLET PORT.